Tag: ozone and its depletion

Depletion of ozone layer is noticed all over the earth.
Ozone is destroyed by collisions with other atoms and molecules.

• An ozone hole is depletion of the ozone layer which is present in the stratosphere region around 26-30kms above the Earth surface. It was first detected in the stratosphere over Antarctica.
• It is caused by chlorofluorocarbons (CFCs) found in air conditioners, aerosol spray cans, refrigerants, etc. CFCs can not be removed in the troposphere and moves in the stratosphere layer where it reacts with ozone, thereby releasing of free chlorine atoms and causes the ozone layer to deplete. 

When the oxygen-depleting substances like CFCs, HFCs, methyl bromide etc. find their way to the stratosphere, the UV rays spilt them to release the reactive species of chlorine and bromine. These reactive species react with the ozone to release the oxygen, thereby causing the depletion of ozone. The ozone hole is the place where the thickness of the ozone layer is very thin and the concentration is less than 220 DU. It is seen over Antarctica due to the process of polar vortex and formation of polar stratospheric clouds.

The main cause of ozone depletion and the ozone hole is manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as ozone-depleting substances (ODS). the United States National Academy of Sciences concluded that credible scientific evidence supported the ozone depletion hypothesis[59] a few countries, including the United States, Canada, Sweden, Denmark, and Norway, moved to eliminate the use of CFCs in aerosol spray cans. The United States banned the use of CFCs in aerosol cans in 1978.[60] The European Community rejected proposals to ban CFCs in aerosol sprays.

Ozone or O$ _3$ is a triatomic gas that forms a layer in the upper part of atmosphere called the Stratosphere. It acts as a shield against harmful radiations of the sun.

The term ozone hole refers to the severe depletion of the ozone layer in the stratosphere, not a literal hole in the physical atmosphere or hydrosphere.

The ozone hole is a massive regional phenomenon, and its area of depletion can indeed cover millions of square kilometers, often exceeding the size of the Antarctic continent.

CFCs (chlorofluorocarbons) were widely used in aerosols and refrigeration and are the primary cause of the ozone layer depletion observed over Antarctica.

The phenomenon of significant ozone depletion over Antarctica is commonly referred to as the Antarctic ozone hole.

Tropospheric ozone is a ground-level pollutant that acts as an irritant to the respiratory system, causing symptoms like chest pain, coughing, and throat irritation.